P1(3) Flashcards
What happens if you use a cathode?
Positive ions gain electrons - reduction
What happens if you use a anode?
Negative ions give up (lose) electrons - oxidation
Where does electrolysis occur?
In a cell , substance to be decomposed is called the electrolyte and the current is passed into and out of the electrolyte by electrodes
What happens if sodium chloride dissolved in water ?
It’s ions become free to love so the solution can be electrolysed
What is a catalyst?
A chemical which is added to a reaction to speed up but can recovered at the end unchanged
What does a catalyst provide ?
An alternate reaction pathway with a lower activational energy
Where does the word redox come from?
Reduction and oxidation , takes place together
What is the test for oxygen?
Glowing splint
What is the test for carbon dioxide ?
Limewater goes cloudy
What is the test for hydrogen?
Squeaky pop
What are chemical changes ?
Chemical reactions often involve changes in energy due to the breaking and formation of bonds
What are chemical changes ?
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances.
Define a mole
A mole of a substance is defined as: The mass of substance containing the same number of fundamental units as there are atoms in exactly 12.000 g of 12C.
How many carbons are in methane , ethane , propane , butane and pentane ?
Methane=1 Ethane=2 Propane =3 Butane=4 Pentane =5
What is the difference between alkenes and alkanes ?
Alkanes only contain single bonds , alkenes contain a double bond
What is the formula for alkanes ?
CnH2n+2
What is the formula for alkenes ?
CnH2n
What is the formula for retention factor (Rf)?
Distance moved by substance / distance moved by solvent
What are formulations ?
Made by mixing components in carefully measured quantities , eg fuels, paints and fertilisers
What is the mobile phase in chromatography?
Water , liquid
What is the stationary phase in chromatography?
Paper
Equation used in chromatography
a/b
What is the test for chlorine ?
Bleached litmus paper white
How many ions are in solutions used in electrolysis ?
4
What is the liquid called in electrolysis ?
Electrolyte
At the negative electrode in electrolysis what stays …
the more reactive one stays in the solution
What are the rules of electrolysis ?
- Write down the ions (positive/ negative )
- Is the positive ion ore reactive than hydrogen? If yes hydrogen is produced. If no, metal is produced
- Is there a halide ion present? If yes the halogen is produced, if no , oxygen is produced
- State what is produced at the anode( positive electron)
